Despite recent advancements in materials and strategies for oil spill remediation, challenges remain in handling the harsh conditions of oil–water separation and enabling the efficient recovery of oil-adsorbing materials. This study reports a facile and effective method to functionalize green-based polyurethane sponge (g-PUS), offering a sustainable alternative to petroleum-based polyurethane sponge (p-PUS), making it with superhydrophobicity, fire resistance, and enhanced stability in water. Accordingly, dodecyltrimethoxysilane-functionalized Fe₃O₄@SiO₂ core-shell nanoparticles (FSi_RhD), derived from rice husk, were synthesized via a precipitation method. The sponges were then coated with a graphene oxide/diammonium hydrogen phosphate (GD) system, followed by surface functionalization with FSi_RhD and polydimethylsiloxane (PDMS). These processes transformed the sponge surfaces from hydrophilic to superhydrophobic, achieving water contact angles (WCA) of 150.9° and 150.3° for the modified g-PUS (M-g-PUS/GD) and p-PUS (M-p-PUS/GD), respectively, while also enhancing synergistic flame resistance. The incorporated magnetic nanoparticles allowed for easy recovery and directional control of the sponges after oil adsorption. Furthermore, the superhydrophobic nature of the modified sponges facilitated efficient oil-water separation and the demulsification of oil in water emulsions. Notably, the M-g-PUS/GD exhibited superior fire resistance characteristics. Conversely, the M-p-PUS/GD demonstrated a slightly higher oil adsorption capacity. Nevertheless, with its improved fire safety and strong oil adsorption capacity, the M-g-PUS/GD emerged as a promising and potentially superior alternative to petroleum-based options for oil spill management. This approach offers a promising strategy for addressing oil spills and inspires further research in this area.